Wool chlorination process



WOOL CHLORINATION PROCESS Lloyd 0. Koons, Ventnor, N. J., and Edwin C.Dreby 3rd, Jenkintown, Pa., assignors to Scholler Brothers, Inc.,Philadelphia, Pa., a corporation of Pennsylvania No Drawing. ApplicationNovember 6, 1953, Serial No. 390,740

9 Claims. (Cl. 8-128) The present invention relates to processes ofchlorinating Wool.

This application is a continuation-in-part of our copending application,Serial No. 27,364, filed May 15, 1948, for W001 Chlorination andProcess, now abandoned.

A purpose of the invention is to control the character and extent of thephysical and chemical change of the Wool in chlorinating the same.

A further purpose is to permit more reliable and controllabledevelopment of nonfelting properties in Wool.

A further purpose is to minimize the yellowing in the chlorination ofWool.

A further purpose is to increase the uniformity of the chlorinatedproduct.

A further purpose is to permit chlorination of fabrics and other similarmaterials which include blends of wools of various character or blendsof wool and other fibers.

A further purpose is to avoid causing harshness in the hand of Wool dueto chlorination.

A further purpose is to avoid fiber damage and particularly to avoidsubstantial increase in the alkali solubility of Wool due tochlorination.

A further purpose is to control the chlorination of wool in an alkalinebath by acidity previously imparted to the wool fiber.

A further purpose is to produce a shrink-resistant wool which willWithstand laundering.

A further purpose is to secure shrink resistance by a treatment whichwill not produce serious color effects on properly chosen dyes, and willhave a minimum of influence on dyeing.

A further purpose is to chlorinate wool by treating the Wool with anacid in solution, retaining in the wool acid amounting to at least 0.3milliequivalent per gram of air dried clean wool fiber and as much as0.7 milliequivalent, and permissibly as much as 2 milliequivalents, andtreating the wool with a chlorinating agent in water solution whilemaintaining a pH range in the solution of at least 7.2 and desirably upto 9, and permissibly as high as 11.5, for a time of two seconds to tenminutes (preferably 20 seconds to five minutes), wool being retainedthroughout the chlorination.

A further purpose in a batch process is to use from 0.3 to 0.7milliequivalent per gram of air dried clean wool fiber (and preferably0.4 to 0.6 milliequivalent) retained in the wool, and to apply thechlorinating agent, preferably a hypo-chlorite, in a maintained pH rangeof the water solution of 7.2 to 9 with a chlorine content of 0.075% to0.4% available chlorine on the weight of the solution at a temperatureof 32 to 100 F., preferably 70 to 80 F. for a time in excess of oneminute and preferably not exceeding minutes, but permissibly up to 10minutes.

A further purpose in a continuous process is to treat wool with acid insolution, retaining in the wool acid amounting to 0.3 to 2milliequivalents per gram of airdried clean Wool fiber, and then with,or without interruption between the acid addition and the subsequentstep to treat the wool continuously with a chlorinating agent,preferably a hypochlorite in water solution containing 0.2 to 2%(preferably 0.5 to 1.5%) available chlorine on the weight of thesolution, while maintaining a pH range in the solution of 7.2 to 11.5,for a time of 2 seconds to 1 minute at a temperature of 32 to 100 F.,acidity in the wool being retained throughout the chlorination.

acidity in the A further purpose is to maintain the pH range bybuffering, preferably by alkaline sodium borate.

A further purpose is to cause the absorption of an acid compound in thewool, to regulate such acidity to a desired amount, and then to bringthe wool into contact with an alkaline bath containing'combinedavailable chlorine, preferably as calcium or sodium hypochlorite, inwhich gradual and controlled chlorination will take place as thehypochlorite encounters the acidity in the Wool.

For many years it has been the practice to chlorinate wool for thepurpose of altering the structure, either chemically or physically, ofthe fibers so as to reduce shrinkage caused by felting or to reduce thediiferential coefficient of friction of the fibers or the tendency ofthe fibers to interlock with one another.

Chlorination has no effect on shrinkage due to fiber and fabricrelaxation. The essential effect is believed to be one of altering thesurface characteristics of the scale structure of the fiber, so that thefibers exhibit a reduced differential coelficient of friction.Chlorinating of wool has also been applied for other purposes, althoughthe primary purpose has usually been to reduce shrinkage.

In the prior art practice of chlorinating wool, several difficultieshave been encountered which have interfered with the success of theoperation or made the process troublesome. One of the primary prior arttroubles has been through yellowing of the wool, and one of theimportant advantages of the present process is that yellowing isminimized or wholly eliminated.

In the prior art practice in some cases the scale destruc tion has beenso extensive that the wool has been structurally impaired, so that thefibers have been actually weakened and embrittled to such an extent thatthe resilience is reduced. The present process permits eifectiveicillorination Without any such undesirable effect on the ers.

In many prior practices the wool has been seriously damaged, asevidenced by marked increase in alkali solubility, Whereas in accordancewith the present invention no appreciable damage is caused and only aslight increase in alkali solubility results from the chlorination.

In order to overcome some of these diificulties, prior art practiceshave in many cases been modified so as to protect the fiber, and suchmodifications have often prevented effective elimination of felting. Bythe present invention the shrinkage of fine wool can be reduced to belowfive per cent, and the shrinkage of coarse wool can be reduced to belowtwo percent, reliably and uniformly.

In the prior art chlorination, much dilficulty has been caused by theharshness produced in the hand of the Wool. The process of the presentinvention has no undesirable effect on the softness and natural feel ofthe fiber.

Great difliculty has been encountered in the prior art in obtaininguniform results. The present invention greatly increases the uniformity,to such an extent in fact that blends of coarse and fine Wool may beprocessed together with highly satisfactory results. The presentprocess, furthermore, can be applied uniformly to blends of wool withother fibers, such as cotton, rayon, nylon and the like, such otherfibers going through the process unchanged and Without harm. Animportant feature of the present invention is that the various types ofwool, including the extremely coarse and extremely fine varieties,absorb acid to approximately the same extent, and such absorbed acid canbe used to control the chlorination in an alkaline bath.

Further purposes appear in the specification and in the claims.

When reference is made herein to Wool, it is intended to refer to animaltextile fibers of the character of Wool, wlhether sold as wool, lama,alpaca, animal hair or the li e.

' Not only is the shrink-resisting treatment of the present inventionuniform and controllable, but the results obtained are reproducible.Furthermore, the treatment of the present invention, unlike some ofthose employed in the prior art, withstands laundering.

One difiiculty with the prior art chlorinating techniques has been thatin many cases if applied to undyed wool they affect the evenness ofdyeing, and if applied to dyed wool they cause marked changes in color.The processof the present invention has little or no effect on evennessof dyeing if applied to undyed Wool, and can be applied on properlyselected dyestuffs if applled to dyed wool.

From a commercial standpoint, the process of the in vention is desirablebecause it operates at relatively high speed, and makes efficient use ofchlorine.

'In carrying out the process, it is immaterial whether the wool isinitially acid or alkaline.

The chlorination may be applied in the yarn, raw stock, sliver, roving,top, fiber or fabric. The process may be applied preferably beforescouring, but it may also be applied after scouring if desired.Likewise, the wool may be dyed before or after chlorination, although ofcourse, if the dyeing is accomplished before chlorination, the dye mustbe fast to chlorine. To obtain good whites, the chlorination shouldpreferably be applied before peroxide bleaching.

The process of the invention can be applied after carbonizing, in whichcase the carbonizing acid in the wool can be employed to control thechlorinating process.

Likewise the process of the invention can be applied batchwise orcontinuously as desired.

All percentages herein are based on the total dry weight of the goodsbeing treated, unless otherwise indicated.

The goods or other material being treated are first treated with acid tocause the wool to take up the required acid content to control thechlorination. The acid may be applied by spraying or otherwise, but thegoods will preferably be clipped or soaked in the acid.

The acid content may be adjusted by partial neutralization, so as tobring the quantity of acid to the desired level.

"If the pure acid is a liquid, it may be applied as such liquid, or itmay be applied in water solution.

The acid content retained in the wool when it enters the chlorinatingbath should be at least 0.3 (preferably 0.4) milliequivalent per gram ofclean air dried wool fiber. For batch operation it is best not to havethe acid content in excess of 0.7 (preferably not in excess of 0.6)milliequivalent per gram as aforesaid. This is particularly suitable fortime ranges of l to 10 minutes, preferably 1 to minutes at a pH of 7.2to 9 as later explained.

Particularly for continuous operation and particularly for short times(2 seconds to one minute and especially less than 20 seconds) the acidin the wool may be built up to much higher levels, as high as 2milliequivalents per gram as aforesaid. Also acid contents as low as 0.3milliequivalent per gram may be used for such short times, but these arenot preferred, and for best results the acid retained should exceed 0.7milliequivalent per gram. It is not desirable to use acid contents inexcess of 2 milliequivalents per gram as aforesaid, even with theshorter times (down to a minimum of two seconds). It will be understoodthat the upper limit of acid content is set by the desire to avoiddamage to the wool, and that if the temperature is kept down below 100F., preferably at sub-atmospheric temperatures, large quantities of acidcan be tolerated for short times.

In any case it will be evident that the acid content in the Wool issufiicient so that it is not fully neutralized by the alkalinechlorinating bath and the wool still contains acid unneutralized at theend of the chlorination.

The preferred acid for use for acidulating is sulphuric acid in the formof sodium bisulphate. Other acids may be used. If sodium bisulphate isnot desired, potassium bisulphate, or other alkali metal bisulphate,sulphuric acid or a mixture of sulphuric and oxalic acids, sulphuric andhydrochloric acids or the like may be used. Instead of the above,oxalic, hydrochloric, phosphoric, formic, propionic, glacial acetic,chloracetic, trichloracetic, or other acid to secure the desired aciditymay be employed. For the purpose of the present invention phosphoricacid acts as a monobasic acid.

A wetting agent, such as an alkyl aryl sulphonate may desirably beemployed to accelerate the treatment of the Wool by the acid, but theprocess can readily be carried on without such Wetting agent. Where thewetting agent is used, it may conveniently be employed in a proportionof about 4 the weight of the acid; thus if sodium bisulphate is used,the dry composition may be 98% sodium bisulphate and 2% alkyl arylsulphonat he e P centages are of the dry composition).

The temperature of the acid solution can vary, the preferred temperaturebeing about 130 F., although lower temperatures down to or below roomtemperature and higher temperatures for example up to the boilingtemperature of water can be used.

Of course it will be understood that where the wool is being carbonizedand carbonizing acid is in the Wool, much higher temperatures will beused for short times in connection with the baking in carbonizing, andthe acid content in the wool will often be of the order of 4 to 6% ofresidual sulphuric acid, or in general 2 to 10 percent of acid.

The effect of the treatment of the wool with the acid as just notedcauses the wool to take up a large quantity of acid and if the acidquantity is excessive for the control purposes desired, the acid contentcan be partially neutralized before chlorination. Also, of course, acidcontent should be removed from the wool by squeezing or draining beforechlorinating. For the short time process particularly, operatingcontinuously at times less than one minute, the water content in thewool leaving the squeeze rolls from the acid treatment at the beginningof chlorination should not exceed percent on the weight of the wool.

The partial neutralization of the wool with alkali before chlorination,while retaining at least 0.3 milliequivalents per gram of acid in thewool, is desirable particularly in the batch process as giving increaseduniformity and reliability by eliminating the delay and uncertainty dueto presence on the wool of acid which is not combined with the fiber butmerely held on the mass of Wool and which otherwise is likely to reactwith and waste hypochlorite.

The alkali which is used in case of partial neutralization of the woolbefore it enters the chlorinating bath will preferably be sodiummetaborate, but other alkalies may be used, such as borax, potassiummetaborate or other alkaline borates (preferably of alkali metals),sodium carbonate, potassium carbonate or the like.

Considering now the chlorination bath in detail, this bath will bealkaline at the beginning of chlorination and will remain alkalinethroughout the chlorination notwithstanding that the wool is acid evenat the end of chlorination. The pH of the chlorinating bath will at alltimes be in excess of 7.2. It is not desirable to use a pH in thechlorinating bath in excess of 11.5. In the batch process the pH in thechlorinating bath is very desirably kept below 9, as the time ofchlorination is preferably 1 to 10 minutes and most desirably 1 to 5minutes, and in this time some yellowing may occur if the pH of thechlorinating bath is in excess of 9. In the case of continuousoperation, with times not in excess of one minute and preferably between2 and 20 seconds, the chlorinating bath will have a pH of 7.2 to 1 1.5and preferably 8 to 11.5.

While the pH may drop during chlorination, it will not drop below about7.5 and certainly not below 7.2.

The pH in the chlorinating bath may be kept within the desired range inany suitable manner. An automatic pH control and feeder may be used toadd alkali as required to maintain the limits. The limitation may alsobe maintained by buffering, using any suitable buffer, preferably sodiummetaborate or other alkali metal metaborate. Where a buffer is used inthe batch process it will preferably hold the pH between 7.2 and 9.

The temperature of the chlorinating water bath will be maintainedbetween 32 and 100 F., and preferably between 70 and 80 F. Thepercentage of available chlorine should be between 0.075 and 2% of theweight of the solution. In the batch process 0.075 to 0.4% availablechlorine on the weight of the solution is preferably used and in thecontinuous process 0.2 to 2% (most desirably 0.5 to 1.5%) of availablechlorine on the weight of the solution is preferably used. Higherchlorine content may be used for finer wool.

The chlorinating solution preferably consists of a hypochlorite. In thebatch process calcium hypochlorite which should contain at least 70%available chlorine on the weight of the hypochlorite is preferably used.For the continuous process other chlorinating agents such as sodiumhypochlorite or potassium hypochlorite are preferable.

Where the batch process is being used, the preferred technique is tomake up a partial neutralizing solution such as sodium metaboratedissolved in warm water and run the goods in it for at least 30 minutesthen add a stabilizing solution of sodium metaborate in warm water andagitate the goods in it at least one minute and finally add the solutionof chlorinating agent with additional sodium metaborate and run thegoods for the short period of chlorination, which should not exceed tenminutes and preferably be one to five minutes as already explained. Theactual chlorination is completed in about two minutes, using acidcontents of 0.3 to 0.7 milliequivalent per gram of air dried clean woolfiber and preferably 0.4 to 0.6 milliequivalent per gram and using pHranges of 7.2 to 9.

The time may be as short as 2 seconds, especially with acid contents of0.7 to 2 milliequivalents per gram of air dried clean wool fiber in thecontinuous process and permissibly with pH ranges of 7.2 to 11.5,preferably 8 to 11.5. For best results the continuous process will berun from 2 seconds to 20 seconds. Chlorinating beyond ten minutes isundesirable due to yellowing. The chlorination should be stopped at theend of the time. If the chlorinating agent is used up, it will besufiicient to run the goods through squeeze rolls in the continuousprocess, but in most cases the chlorination will be stopped by using anantichlor such as sodium bisulphite, although any other suitableantichlor can be used.

The goods at the end of chlorination and before adding the antichlor areslightly acid and the acidity in the wool is never fully neutralized inthe process. Thus the process of the invention is characterized bychlorination of wool containing retained acid in an alkaline bath, thusavoiding the extremely rapid chlorine release and greater wool damagedue to chlorinating in an acid bath. The control of the batch process isthrough the acid in the wool, which is regulated to the desired levelbefore chlorinating. As long as the. chlorinating bath has a pH withinthe desired range the pH can vary somewhat in that range withoutafiecting the result providing the acidity in the wool is the same ineach case. Control can be secured by the acidity in the wool withoutregard to the exact pH of the chlorinating bath within the range.

Thus though the process produces a rapid chlorination the eifect isgradual, the chlorine being released as the hypochlorite encounters theacid in the wool. As soon as some chlorination has occurred at one pointon the wool fiber, especially in the batch process, the potential forfurther chlorination at that point is lowered by reduction in the acidcontained in the fiber at the point where chlorination has occurred.

If the goods are to be subsequently dyed or bleached they desirablyshould be neutralized and scoured according to any accepted procedure.One satisfactory method is to run for twenty minutes in a bath at 120 F.containing a synthetic detergent (fatty alcohol) and 2% by weight ofsoda ash. This treatment will leave the goods clean and slightlyalkaline which is the optimum condition for starting to dye chlorinatedwool or for bleaching. The neutralizing and scouring bath should bedropped and followed by one warm rinse before dyeing or bleaching.

In some cases it is necessary (ingrain knit hosiery or piece goods) andin other cases it is preferable (on light blues, pinks, and other likeshades where levelness is a problem even on untreated wool) tochlorinate after dye ing. This can be done provided the dyes are fast tochlorine. No special precaution need be taken except for thoroughrinsing after dyeing.

The equipment used for the process should be stainless steel, Monelmetal, wood, rubber, plastic or a similar material, which is resistantto chlorine. No particular change in the process is required withvariation in the type of equipment. The amounts of the chemicals usedand the preferred temperatures remain unchanged. In some machines,however, the time of processing should be changed for best results andother precautions should be taken to assure maximum uniformity.

EXAMPLE I The following is a typical example of chlorination in a batchprocess: One hundred pounds of goods containing 90% wool are to bechlorinated, to be subsequently dyed and not bleached. The volume of thebath required for the proper handling of the goods in the equipment usedis 240 U. S. gallons or 2,000 pounds. Dividing the weight of the bath bythe weight of the goods, it is determined that the bath ratio is 20.Since the goods are to be subsequently dyed but not bleached, the tablesused as set forth immediately after these examples are Table 1-D toTable 4-D.

In Table l-D, the left hand column is headed Bath ratio, and readingdown to 20 you then read horizontally to the column headed wool ingoods. The quantity required of sodium bisulphate (98%) plus alkyl arylsulphonate (2%) for the acidulation is 23% of the dry weight of thegoods. The quantity of sodium metaborate for partial neutralization forall bath ratios as shown by Table 2-D for 90% wool in the goods is 3%%.Table 3-D for the calcium hypochlorite, and Table 4-D for the sodiumbisulphite read similar to Table 1D, indicating that 4% of calciumhypochlorite and 3% sodium bisulphite are to be used.

With sulphuric acid (including sodium bisulphate) the pH may vary from 1to 4 in the acidulating bath, although a pH from 3 to 4 is notpreferable because of the length of treatment time required. A pH below1 is not recommended because of the tremendous quantity of acidrequired, and the likelihood of undesirable effects on the laterprocessing.

The quantity of acid will, of course, vary with the particular acid.Where sodium acid sulphate is used, the quantity of this compound plus2% wetting agent is given in Table 1-D for goods subsequently to be dyedor left natural, and by Table lB for goods which are subsequently to beperoxide bleached. The quantity of acid may vary widely, and even whenit is desired to keep close to the conditions specified to obtainmaximum uniformity of results, the acid plus wetting agent may varyeither way by 20% of such percentage (provided the acid retention iskept within the limits set).

A bath is prepared at 130 F., the acid (plus wetting agent, if used),previously dissolved and diluted is added to the bath, the goods enteredand run or agitated for 20 minutes. The bath is then drawn oil. and thegoods drained well. The goods should not be rinsed at this point.

The excess of acidity is preferably next neutralized in a cold waterbath (about 70 F.80 F.), by adding sodium metaborate (previouslydissolved), in the amount specified in Table 2D for goods subsequentlyto be dyed or left natural, and in Table 2-B for goods subsequently tobe peroxide bleached. The machine is then run for approximately thirtyminutes. By the end of this treatment a sufficient degree of equilibriumhas been attained between the acid in the wool and the added sodiummetaborate to give the desired degree of acidity.

Next preferably 1% of buffer (preferably sodium metaborate) is added (inwater solution) to the first alkali bath, and the goods run for oneminute.

Next, the chlorination solution (prepared as described below) is addedto this bath and goods run or agitated for five minutes.

Next, the antichlor, sodium bisulphite (previously dissolved in warmWater), is added to this bath, the amount used being as indicated byTable 4-D or Table 4-3 (depending on the subsequent processing of thegoods). The antichlor should be agitated or run with the goods for aboutten minutes, after which the entire bath is dropped and two warm rinsespreferably at 90 to 100 F. are applied.

The preferred manner of making up the chlorinating solution is todissolve in warm water two percent of sodium metaborate buffer on thedry weight of the goods, and separately dissolve in warm water theamount of calcium hypochlorite indicated by Table 3D or Table 3-Bdepending on whether the goods are to be dyed or left natural on the onehand or are to be peroxide bleached. The calcium hypochlorite ispreferably sifted slowly into ten to twenty times its own weight ofwater with constant stirring. The calcium hypochlorite does not entirelydissolve, but the solution remains turbid. The sodium metaborate andcalcium hypochlorite solutions are then combined by pouring the formerinto the latter while stirring.

It is desirable to take special precautions on goods which aresubsequently to be peroxide bleached. Peroxide bleaching imparts acertain amount of shrink resistance to the wool fiber, and therefore itis desirable to give a milder treatment than would be given to woolwhich is subsequently to be dyed or which is to receive no furthertreatment. Accordingly when the wool is subsequently to be peroxidebleached, Table 1-B to Table 4-13 should be followed, which specify asomewhat higher concentration of alkali in the pretreatment bathimmediately prior to chlorination, and a somewhat lower content ofhypochlorite in the chlorinating bath, as well as a somewhat lowercontent of antichlor.

No special change in the bleaching procedure need be made.

By referring to the tables, it will be seen that on the weight of thegoods the sodium bisulphate varies from 7.8 percent to 34.4 percent forthe acid bath, for the neutralization and buffering, the sodiummetaborate varies from 4 /2% to 10%, the calcium hypochlorite variesfrom 1%% to 6%.%, while in the antichlor the sodium bisulphite variesfrom 2% to 4 /2%. Where the goods are subsequently to be dyed or leftnatural, the sodium bisulphate in the acid bath varies from 7.8% to34.4%, and in the neutralizing and chlorinating bath the total sodiummetaborate varies 'from 4 /2% to 7%, the calcium hypochlorite variesfrom 2 /2% to 6 /2% and the antichlor varies from 2% to 4 /2% Where thegoods are subsequently to be bleached, the sodium bisulphate varies from7.8% to 34.4% in the acid bath, in the neutralizing and chlorinatingbath the total sodium metaborate varies from to 10% and and the calciumhypochlorite varies from 1%% to 5 while the antichlor varies from 2% to3%.

EXAMPLE II In the batch process, the entire procedure may be carried outin a single bath, rather than using the separate baths as in Example I.Ten percent of the acidic composition (98% of sodium bisulphate and 2%of wetting agent) is made up in a bath using a 20 to 1 bath ratio. Thegoods are run in this bath at 100 F. for forty-five minutes. Then 2% ofsodium metaborate is added and the bath run for five minutes. Followingthis the chlorination is carried on as in Example 1 employing 5% ofcalcium hypochlorite and 2% of sodium metaborate, and following with theantichlor as in Example I.

It will be understood that in this one bath method the proportions maybe varied as indicated in the tables for different goods compositions,provided recognition is given to the fact that the acid is not beingdrained from the goods or removed from the bath but must be neutralizedprior to the chlorination.

EXAMPLE III The procedure of Example I is followed out except that theacidulation is accomplished in a bath containing 17% oxalic acid, basedon the weight of goods being treated.

EXAMPLE IV The procedure for continuous chlorinating according to theinvention, was applied to cloth in the piece consisting of a wool-nylonshirting woven from yarn made from single ply 45% fleece and/ or oldwool, not lower in grade than 62s U. S. standard, from 10 to firstquality staple nylon of about 1 /2 inches staple length, and not morethan 40% of wool noils not lower in grade than 62s U. S. standard. Thecloth was carbonized in the usual manner, running it through a sulphuricacid bath at 2 Baum maintained at 70 to 80 F, and was then carriedthrough a usual carbonizing oven, having a temperature of 180 F. in thefirst chamber, 200 F. in the second and third chambers, and 260 F. inthe fourth and fifth chambers. The running time in the carbonizing bath,was two minutes, and the running time in the baking oven was 2.5 minutesper chamber.

After carbonizing, the acid content in the wool was 1.225milliequivalents per gram of air dried clean wool fiber. Good resultswere obtained even when the wool containing the acid was held for acouple of days before chlorinating.

The cloth containing the above acid content, was run into a chlorinatingbath which had a pH of 10.0 maintained plus or minus 0.2 by meteredadditions of sodium hydroxide. The chlorinating bath contained 0.5%available chlorine. The chlorinating bath was maintained at atemperature of 70 to 80 F. by cooling coils under the control of atemperature controller.

The chlorinating was carried out in a continuous padding machine with atime exposure of the cloth to the chlorinating bath between eight andten seconds. The chlorine consumption was 0.027 pound per pound offabric. a

After chlorinating, the cloth was immediately run Tables I-D to 4-D[These tables apply only on goods that are to be subsequently dyed orleft natural.]

PERCENT OF WVOOL IN GOODS Bath Ratio 1.00 80 70 60 50 40 30 20 TABLE l-DPercentage of sodium bisulphate (98%) plus alkyl aryl sulphonate (2%) 16l5 14 13 12 ll 10 9 8 18 17 16 15 14 13 12 11 10 21 20 19 18 17 16 15 1413 24 23 22 21 20 19 IS 17 16 27 26 25 24 23 22 21 20 19 29 28 27 26 2524 23 22 21 31 30 29 28 27 26 25 24 23 35 34 33 32 31 30 29 28 27 TABLE2-D Percentage of sodium metaborate for partial neutralization TABLE 3DPercentage of calcium hypoehlorite TABLE 4-D Percentage of sodiumbisulphite Tables l-B to 4-B PERCENT YVOOL IN GOODS Bath Ratio 100 90 8070 60 50 40 30 20 TAB LE 1-B Percentage of sodium bisulphate (98%) plusalkyl aryl sulphonate (2%) TABLE 2-1;

Percentage of sodium metaborate for partial neutralization All 7 6% 5% 4/2 4 3 /2 2% TABLE 3-B Percentage of calcium hypoehlorite TABLE 4-BPercentage of sodium bisulphite Table 5 Felting Alkali Comm ShrinkageSolubility Medium blue twill l. i% gfi:: }15.40%

I 1007 w l twill 8 0O weave zgg gg dz. medium blue in milli- Time in pHof bath equivalents Seconds Increase per gram of Felting in Alkali airdried wool Shrinkage Solubility s 1. c 2 {$3,25 }3.70%. s 1. s 8 Tf 1}4.75% W -3.5%- m 1.2 s g }2.c0/., s 0. 4 32 2 1 }2.75%.

W warp F: filling.

To avoid relaxation shrinkage, tension in operating subsequent tochlorinating was kept at a minimum. The subsequent operations includedoverfeed tentering, shearing, sponging and semi-decating.

The results were well within commercial limits. For example, on acellulose-acetate-wool fabric, treated in accordance with the generalprocedure as outlined above, the average shrinkage after washing was0.5%.

EXAMPLE V I In Example V, a twill weave 100% wool fabric dyed a mediumblue having a weight of 8 ounces per lineal yard inches wide) wastreated. The cloth was cut into strips 9 inches wide and approximatelyone yard long to be used in the test.

The cloth was first given a treatment with acid to make it takeup acidto the desired content, and then it was run into the chlorinating bath,through squeeze rolls, through a cold water rinse, and then into aneutral bath.

The chlorinating bath was maintained at a temperature of from to F. andit contained 0.57% of available chlorine at the start of the test, and0.48% at the end.

The time of chlorination was controlled by varying the speed of thesqueeze rolls, and was measured from the instant the cloth contacted thechlorinating bath until it passed the squeeze rolls.

The neutralizing bath was maintained at a temperature from 80 to F. andconsisted of a 1% sodium bicarbonate solution by weight. The cloth wasretained in the neutralizing bath for two minutes in each case. Thecloth was then rinsed three times for a total of fifteen minutes, toremove all soluble chemicals.

Following the chlorination, the cloth was given four, thirty minutewashes with 0.5% soap at 140 F. followed by three, ten minute rinses at140 F. in a Najort washer and the felting shrinkage was measured forboth the warp and the filling. The average value in each instance forfour measurements, is given in Table 5. In some cases, the dimensions ofthe cloth actually increased, as indicated by minus values. The increasein alkali solubility was also determined with respect to controls.

It will be evident that the felting shrinkage values and the alkalisolubilities are within satisfactory commercial limits.

EXAMPLE VI Tests were conducted on wool-rayon fabrics, of which thefollowing is typical. An 8 ounce fabric (8 ounces per lineal yard, 57inches wide) woven from yarns containing 60% wool fibers and 40% viscoserayon fibers, was passed into a solution of 6% by weight of formic acidin water, and then through squeeze rolls to a pick up of 6% by weight offormic acid in the cloth. The acidulated cloth was then passed wet intoa chlorinating bath containing hypochlorite, having a concentration ofavailable chlorine of 0.5 for a time of from eight to ten seconds. Thechlorinating bath had a pH of 10 maintained during the chlorination. Thetemperature of the chlorinating bath was maintained at from 70 to 80 F.The material was passed through squeeze rolls from the chlorinatingbath, and then into a neutralizing bath containing 1% sodium bicarbonatein water at 80 to 90 F. Following the neutralizing bath, the materialwas scoured and finished. The alkali solubility was increased about 10%with the procedure, and the felting shrinkage after four standardwashes, was 3% in the warp, and less than 2% in the filling.

It will be understood that for other acids, alkaline and chlorinatingagents, the percentages will be varied to produce the particularacidities and chlorine availability values desired.

The present invention has been successfully applied to the chlorinatingof a wide variety of wools under varying conditions of blends andmixtures with other fibers, and has been found to impart uniformchlorination and reliable non-felting properties, without harm to thephysical properties, such as structure and resilience of the fibers, andwithout appreciable yellowing or other undesirable eifect.

It is possible to employ the same chlorinating bath or a chlorinatintgbath of the same composition to pro duce different degrees ofchlorination by changing the acidity of the wool within the rangespecified, the extent of the chlorination increasing with the acidityand reducing with reduction of the acidity. It will be understood thatsuch control of the chlorination is possible notwithstanding widevariation in the pH in the chlorinating bath within the limits setforth.

In view of our invention and disclosure variation and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of ourinvention without copying the process and composition shown, and we,therefore, claim all such insofar as they fall within the reasonablespirit and scope of our claims.

Having thus described our invention what We claim as new and desire tosecure by Letters Patent is:

1. The process of chlorinating wool, which comprises treating the woolwith acid in solution, retaining in the wool acid amounting to 0.3 to 2milliequivalents per gram of air-dried clean wool fiber and treating thewool with a chlorinating agent in water solution while maintaining a pHrange in the solution of 7.2 to 11.5, for a time of 2 seconds to 10minutes, at a temperature of 32 to F. acidity in the wool being retainedthroughout the chlorination.

2. The process of claim 1, wherein the acid retained in the wool issulphuric acid.

3. The process of chlorinating wool in a batch process, which comprisestreating the wool with acid in solution,

retaining in the wool acid amounting to 0.3 to 0.7 milliequivalent pergram of air-dried clean wool fiber, and treating the wool with achlorinating agent in water solution, while maintaining a pH range inthe solution of 7.2 to 9, for a time of 1 to minutes, at a temperatureof 32 to 100 F., acidity in the wool being retained throughout thechlorination.

4. The process of claim 3, wherein the acid retained in the wool is from0.4 to 0.6 milliequivalent.

5. The process of claim 3, wherein the chlorinating agent is buffered byalkaline sodium borate.

6. The process of claim 3, wherein the acid is from 7.8 to 34.4 percentof sodium bisulphate on the weight of the goods in water solution, andthe chlorinating solution contains from 4.5 to 10 percent on the weightof the goods of sodium metaborate and from 1.75 to 6.5 percent on theweight of the goods of calcium hypochlorite having an excess of 70percent of available chlorine calculated on the weight of calciumhypochlorite.

7. The process of claim 3, wherein the amount of acid retained in thewool is not in excess of 0.6 milliequivalent and the chlorinatingsolution contains from 1.75 to 6.5 percent of calcium hypochlorite onthe weight of the goods having in excess of 70 percent of availablechlorine on the weight of the calcium hypochloritc.

8. The process of chlorinating wool in a continuous process, whichcomprises treating the wool with acid in solution, retaining in the woolacid amounting to 0.3 to 2 milliequivalents per gram of air-dried cleanwool fiber, and treating the wool with a chlorinating agent in watersolution containing from 0.2 to 2% available chlorine on the weight ofthe solution, while maintaining a pH range in the solution of 7.2 to11.5, for a time of 2 seconds to 1 minute, at a temperature of 32 to F.,acidity in the wool being retained throughout the chlorination.

9. The process of claim 8, wherein the amount of acid retained in thewool is from 0.7 to 2 milliequivalents and the pH during chlorination ismaintained in the range between 8 and 11.5.

References Cited in the file of this patent UNITED STATES PATENTS2,132,345 Reichert Oct. 4, 1938 2,457,033 Clapham et a1. Dec. 21, 19482,466,695 Frishman Apr. 12, 1949 2,508,007 Bloch May 16, 1950 FOREIGNPATENTS 669,247 France Nov. 13, 1929 OTHER REFERENCES

1. THE PROCESS OF CHLORINATING WOOL, WHICH COMPRISES TREATING THE WOOLWITH ACID IN SOLUTION, RETAINING IN THE WOOL ACID AMOUNTING TO 0.3 TO 2MILLIEQUIVALENTS PER GRAM OF AIR-DRIED CLEAN WOOL FIBER AND TREATING THEWOOL WITH A CHLORINATING AGENT IN WATER SOLUTION WHILE MAINTAINING A PHRANGE IN THE SOLUTION OF 7.2 TO 11.5, FOR A TIME OF 2 SECONDS TO 10MINUTES, AT A TEMPERATURE OF 32 TO 100* F. ACIDITY IN THE WOOL BEINGRETAINED THROUGHOUT THE CHLORINATION.